This Training Grant, now entering its 25th year, provides support for a unique interdisciplinary pre-doctoral and post-doctoral training program in Immunology at the Johns Hopkins University School of Medicine. The Training Grant is the core source of funding for the Graduate Program in Immunology. The mission of this Interdepartmental program is to provide students and fellows with training in cellular, biochemical, and genetic approaches to the biology of the immune response. We seek to provide trainees with the ability to identify significant research questions in immunology, to find solutions to these questions, to think broadly and creatively about biological problems, and to communicate ideas effectively to others. There are 34 faculty members who participate in the program and provide a broad range of training opportunities for students and fellows. These areas include genetic and cellular Aspects of immune development, T cell antigen recognition, immune regulation, tolerance, structural biology immune proteins, complement, innate immunity, autoimmunity, immune cell signaling, cancer immunology, IgE-mediated immunologic reactions and the host response to infection. In these areas, the training environment is enhanced by institutional strength in relevant areas of basic science and/or clinical medicine. Cross-fertilization between basic research and clinical disease studies is an important aspect of the training environment. The predoctoral program places emphasis on rigorous training in basic biochemistry and molecular and cellular biology in addition to immunology. Progress of trainees throughout the didactic and research portions of the pre-doctoral training program is monitored closely through multiple mechanisms. Post-doctoral fellows have the option of selecting laboratories that focus on basic immunology or immunologic diseases. An extensive and successful program for recruiting minority students has been implemented.